Here we seek to understand the neurochemical signals and neurosystems underlying reward-related decision- making. Considerable evidence suggests the decision between actions leading to different rewards relies heavily on the anticipated value of each action's outcome. In addition to this, reward-related decisions are also biased by reward-paired environmental cues, such that a cue predicting a specific reward will bias one towards the action that obtains that reward, even if other, potentially better, options ar available. Regarding the circuitry of reward-related decisions, numerous interconnected structures, including the basolateral amygdala, orbitofrontal cortex and insula are all implicated, but how or if they interact to control decisions remains unclear. Neurochemically, glutamate signaling and neuromodulatory opioid peptides are also implicated in aspects of reward seeking, but how these signals are related to discrete aspects of behavior has not been elucidated. Here we will use a novel glutamate biosensor technology, which allowed us, for the first time, to monitor transient extracellular glutamate concentration changes in the basolateral amygdala of freely-behaving rats, to clarify the role of rapid basolateral amygdala glutamate signaling in both reward learning and decision- making. Moreover, we will explore the basolateral amygdala-cortical circuitry that controls reward-seeking decisions. Given the limited number of signaling molecules in the brain, interactions between them must occur in order to account for the vast number of human behaviors. To this end, we will also explore the regulation of decision-related basolateral amygdala glutamate release by the neuromodulatory opioid peptide systems. The long-term goals of this research trajectory are to characterize the specific neurochemical signals that underlie discrete aspects of decision-making. Importantly, this research aims to identify brain regions and neurochemical systems that interact to underlie decisions driven by reward value as well as those that are biased by environmental cues. Each of these forms of decision-making can be disrupted in addiction to drugs, alcohol or even highly palatable foods. Therefore, information gleaned from this research trajectory will provide the basic science necessary for the development of new pharmacotherapies to combat these specific deviations in addiction and compulsive over-eating. Importantly, the proposed research makes use of a new tool, not yet applied to these questions, in order to provide new information regarding the role of brain glutamate signaling in reward-related behaviors.